#ifndef STAN_MATH_PRIM_SCAL_FUN_INV_SQRT_HPP
#define STAN_MATH_PRIM_SCAL_FUN_INV_SQRT_HPP

#include <cmath>

namespace stan {
  namespace math {

    inline double inv_sqrt(const double x) {
      using std::sqrt;
      return 1.0 / sqrt(x);
    }

  }
}

#endif
